Charge transfer complexes of tetrathio/seleno-fulvalene derivatives and biscyanimine derivatives; biscyanimine derivatives and method for producing same

ABSTRACT

A novel charge transfer complex of an N,N&#39;-biscyanoquinone bisimine of the formula ##STR1## and a fulvalene derivative of the formula ##STR2## where, in formula I, R 1 , R 2 , R 3  and R 4  independently of one another are --H, --CH 3 , --C 2  H 5 , --OCH 3 , --OC 2  H 5 , --Cl and/or --Br, and one of the radicals R 1  and R 2  and/or one of the radicals R 3  and R 4  may furthermore be phenyl or tert.-butyl, or R 1  and R 2  and/or R 3  and R 4  together form ##STR3## and the fused-on aromatic ring is unsubstituted or substituted, and, in formula (II), R 5 , R 6 , R 7  and R 8  independently of one another are each --H, --CH 3 , --C 2  H 5 , phenyl, methylphenyl or methoxyphenyl, or R 5  and R 6  and/or R 7  and R 8  together form ##STR4## where n=3, 4 or 5, ##STR5## and X and Y indendently of one another are each S or Se. In the crystalline state, the charge transfer complex possesses electrical conductivity and accordingly can be used as an electrical semiconductor or photoconductor. 
     Novel biscyanoquinone imines of the formula (I), where R 1 , R 2 , R 3  and R 4  have the stated meanings, and a novel process for the preparation of the compounds (I).

The present invention relates to novel charge transfer complexes basedon biscyanimines.

Charge transfer complexes of tetrathio/selenofulvalenes andtetracyanoquinodimethanes have been disclosed (Synthesis 1976, pages489/514, and J. Chim. Phys. 79 (1982), 299 et seq.).

The present invention relates to novel charge transfer complexes of abiscyanimine of the formula ##STR6## and a compound of the formula##STR7## where R¹, R², R³ and R⁴ independently of one another are eachhydrogen, methyl, ethyl, methoxy, ethoxy, chlorine or bromine, or one ofthe radicals R¹ and R² and/or one of the radicals R³ and R⁴ is phenyl ortert.-butyl, or R¹ and R² and/or R³ and R⁴ together are each a ##STR8##in which the fused-on aromatic rings are unsubstituted ormonosubstituted or disubstituted by chlorine, bromine and/or methyl, R⁵,R⁶, R⁷ and R⁸ independently of one another are each hydrogen, methyl,ethyl, phenyl, methylphenyl or methoxyphenyl, or R⁵ and R⁶ and/or R⁷ andR⁸ together form a ##STR9## and X and Y independently of one another areeach S or Se.

In the charge transfer complexes, the molar ratio of acceptor to donoris, as a rule, 1:1. However, in the case of charge transfer complexeswhich contain dibenzotetrathiafulvene ((II) where R⁵ /R⁶ and R⁷ /R⁸ areeach ##STR10## it is also possible to isolate complexes in which themolar ratio of acceptor to donor is 1:2.

In the crystalline state, the complexes according to the inventionpossess electrical conductivity and accordingly can be used aselectrical semiconductors and photoconductors, for example for theantistatic treatment of plastics, as an electrode or storage material inelectrical batteries, for the production of solar cells, in fuel cells,for the conversion of radiation and for the production of electroniccomponents.

Suitable radicals R¹, R², R³ and R⁴ in (I) are those stated above.

Specific examples are the following: R¹, R², R³ and R⁴ are identical andare each hydrogen, chlorine, methyl or methoxy, or R¹ is chlorine,bromine, methyl, ethyl, methoxy, ethoxy, phenyl or tert.-butyl, and R²,R³ and R⁴ are each hydrogen, or R¹ and R² are identical and are eachchlorine, methyl or methoxy and R³ and R⁴ are each hydrogen, or R¹ andR³ are identical and are each chlorine, methyl, methoxy or phenyl and R²and R⁴ are each hydrogen, or R¹ and R⁴ are identical and are eachchlorine, bromine, methyl, ethyl, methoxy, phenyl or tert.-butyl and R²and R³ are each hydrogen, or R¹, R² and R³ are each methyl and R⁴ is ahydrogen, or R¹ and R² together form a radical of the formula ##STR11##where the fused-on aromatic ring is unsubstituted or monosubstituted ordisubstituted by chlorine and/or methyl, and R³ and/or R⁴ are hydrogen,chlorine or methyl, or R¹ and R² on the one hand and R³ and R⁴ on theother hand together form a radical of the formula ##STR12## and wherethe fused-on aromatic rings are unsubstituted or monosubstituted ordisubstituted by chlorine and/or methyl.

The fulvalene derivatives of the formula II are known (Synthesis 1976,page 489 et seq.).

Preferred fulvalene derivatives are those of the formula II where X andY are each S.

Particularly preferred compounds are those thiofulvalene derivatives inwhich R⁵, R⁶, R⁷ and R⁸ are identical and are each hydrogen, methyl orphenyl, or R⁵ is methyl or phenyl, R⁶ and R⁷ are each hydrogen and R⁸ ishydrogen, methyl or phenyl, or R⁵ and R⁶ on the one hand and R⁷ and R⁸on the other hand together form a ##STR13##

To prepare the novel 1:1 charge transfer complexes, a biscyanimine ofthe formula I is reacted with a fulvalene of the formula II in a molarratio of from 1:1 to 1:2, in a solvent, if appropriate at elevatedtemperatures. Examples of suitable solvents are dichloromethane,chloroform, 1,1,1-trichloroethane, acetonitrile, benzene, toluene,chlorobenzene and dichlorobenzene.

The charge transfer complexes are isolated in a conventional manner byfiltering them off under suction.

In principle, the biscyanimines (I) can be prepared by 2 methods:

(a) by oxidation of an N,N'-dicyano-p-phenylenediamine (III) ##STR14##or

(b) by reaction of a quinone of the formula IV withbistrimethylsilylcarbodiimide (V) ##STR15## in the presence of acatalyst.

Process (a) has the disadvantage that it cannot be used in every caseand that the biscyanamines (III) required as starting materials aredifficult to obtain in many cases. Moreover, the oxidation gives, as arule, a number of by-products which can be separated off only by meansof purification operations involving large losses.

The novel biscyanimines (I) are preferably prepared by process (b),which gives (I) in satisfactory purity.

In the reaction of (IV) with (V), not less than 2, preferably from 2.2to 3, moles of (V) are employed per mole of (IV). Advantageously, thereaction is carried out in an inert organic solvent, eg.dichloromethane, chloroform, 1,1,1-trichloroethane, 1,2-dichloroethaneor acetonitrile, and in the presence of a catalyst. Examples of suitablecatalysts are cesium fluoride, potassium cyanide/crown ethers, such as18-crown-6, and titanium tetrachloride. The last-mentioned compound isthe preferred catalyst.

The Examples which follow illustrate the invention. Percentages for theyields are percentages of theoretical yield, and DDQ isdichlorodicyano-p-benzoquinone.

EXAMPLE 1

634 mg (4.00 millimoles) of N,N'-biscyano-p-phenylenediamine and 2.86 g(12.0 millimoles) of freshly prepared lead dioxide in 100 ml of absolutebenzene are refluxed for 20 minutes, the mixture is filtered undersuction, and the orange filtrate is evaporated down to about 10 ml. 50ml of methylcyclohexane are added, whereupon a flocculent yellowprecipitate separates out. The product is filtered off under suction,and 136 mg of N,N'-dicyano-p-benzoquinone bisimine are obtained. Themother liquor is evaporated down, and a further 30 mg of product areprecipitated with methylcyclohexane. Total yield: 27% of theory.

EXAMPLE 2

634 mg (4.00 millimoles) of N,N'-biscyano-p-phenylenediamine and 2.27 g(10.0 millimoles) of DDQ in 40 ml of absolute benzene are refluxed for22 hours, and the mixture is allowed to cool and then evaporated down toabout 10 ml. 2.34 g of an orange-yellow product are precipitated with 60ml of petroleum ether (bp. 40°/60° C.). Further concentration of themother liquor and precipitation give another 106 mg of product. 1.14 gof the product are chromatographed over a 6×25 cm column filled with0.063-0.200 silica gel from Woelm, methylene chloride being used as themobile phase. The yellow eluate is evaporated down to about 5 ml, and255 mg (87%) of a product of melting point 160°-162° C. (decomposition)are precipitated with 50 ml of 40/60 petroleum ether.

100 mg of product are sublimed at 90° C. under 4×10⁻² mm Hg. 88 mg (70%)of N,N'-dicyano-p-benzoquinone bisimine of melting point 160°-163° C.(decomposition) are obtained.

IR (KBr): 3060 (CH), 2175 (C.tbd.N), 1565 (C═N), 154 cm⁻¹ (C═C).-

UV (acetonitrile): λ_(max) (lgε)=313 sh (4.35), 330 (4.47), 342 (4.45),361 nm sh (4.24).-¹ H-NMR(CH₃ CN): δ=7.40 ppm (mc, 4H).-¹³ C-NMR(CDCl₃): ε=112.88 (C.tbd.N), 128.53, 129.96, 137.81, 138.66, 174.37(C═N), 174.52 ppm (C═N).-MS (70 eV): m/e=156 (100%, M⁺).

EXAMPLE 3

186 mg of crude N,N'-dicyano-2,5-dimethyl-p-phenylenediamine are addedto a solution of 227 mg (1.00 millimole) of DDQ in 10 ml of absolutebenzene, the mixture is refluxed for 4 hours in the absence of moistureand then filtered off under suction, and the filtrate is evaporated downto about 5 ml. 60 mg (33%) of a yellow solid are precipitated with 25 mlof petroleum ether (bp. 40°/60° C.). Recrystallization from 3 ml ofabsolute acetonitrile gives 54 mg (30% of theory) ofN,N'-dicyano-2,5-dimethyl-p-benzoquinone bisimine in the form of yellowplatelets of melting point 320°-321° C.

C₁₀ H₈ N₄ (184.2) Calculated C 65.20 H 4.38 N 30.42 Found C 65.45 H 4.18N 29.80

IR (KBr): 3050 (CH), 2180 (C.tbd.N), 1590 (C═N), 1535 cm⁻¹ (C═C).-UV(acetonitrile): λ_(max) (lgε)=330 sh (4.45), 344 (4.49), 363 nm sh(4.31).-¹ H-NMR (CDCl₃ /TMS): δ=2.25 (d, J=1 Hz; 6H, CH₃), 7.32 ppm (q,J=1 Hz; 2H, -C═C-H).-¹³ C-NMR (CDCl₃ /TMS): δ=16.81 (-CH₃), 113.32(-C.tbd.N), 128.05 (-C-H), 146.64 (C-CH₃), 175.93 ppm (C═N).-MS (70 eV):m/e=184 (100%, M⁺), 157 (78%, M₊ -HCN).

General method (GM1) for the preparation of N,N'-biscyanoquinone imines(I) by reaction of the p-quinone (IV) with (V).

2.00 millimoles of TiCl₄ are added to a solution of 2.00 millimoles ofthe quinone in 6 ml of CH₂ Cl₂. During this procedure, a yellow ororange precipitate is formed. 4.40 millimoles of (V) in 6 ml of CH₂ Cl₂are then rapidly added dropwise, and the mixture is stirred while theprecipitate dissolves. The course of the reaction is monitored by meansof thin layer chromatography (precoated 40×80 mm silica gel plate fromMachery, Nagel & Co., methylene chloride as mobile phase). When thereaction is complete, the reaction mixture is filtered via an Alihn tubehalf filled with a suspension of silica gel (0.063-0.200 from Woelm) inCH₂ Cl₂. The tube is washed with methylene chloride until the eluate nolonger has a yellow coloration. The eluate is then evaporated down in arotary evaporator, and the products are sublimed and/or recrystallized.

EXAMPLE 4

Using method GM1, a solution of 820 mg (4.40 millimoles) of (V) in 6 mlof CH₂ Cl₂ is added dropwise to 216 mg (2.00 millimoles) ofp-benzoquinone and 379 g (2.00 millimoles) of TiCl₄ in 6 ml of CH₂ Cl₂.After 15 minutes, the mixture is filtered over SiO₂, and 156 mg (50%) ofN,N'-dicyano-p-benzoquinone bisimine are precipitated with petroleumether (30°/75° C.). The product is identical to theN,N'-dicyano-p-benzoquinone bisimine obtained as described in Example 1;mp.: 163° C. (decomposition).

C₈ H₄ N₄ (156) Calculated C 61.53; H 2.58; N 35.88; Found C 61.17; H2.54; N 35.37.

EXAMPLE 5

Using method GM1, 272 mg (2.00 millimoles) of2,5-dimethylrp-benzoquinone, 379 mg (2.00 millimoles) of TiCl₄ and 820mg (4.40 millimoles) of (V) in 12 ml of CH₂ Cl₂ are stirred for 3 hours.The mixture is worked up to give 289 mg (78%) of crude product, which isrecrystallized from 10 ml of acetonitrile to give 275 mg (75%) ofN,N'-dicyano-2,5-dimethyl-p-benzoquinone bisimine. Its propertiescorrespond to those of the N,N'-dicyano-2,5-dimethyl-p-benzoquinonebisimine obtained as described in Example 3; mp.: 320° C.(decomposition).

EXAMPLE 6

885 mg (5.00 millimoles) of 2,5-dichloro-p-benzoquinone, 948 mg (5.00millimoles) of TiCl₄ and 2.05 g (11.0 millimoles) of (V) in 15 ml of CH₂Cl₂ are reacted by general method GM1. After 3 hours, the mixture isworked up to give 486 mg (43%) of crude product of melting point 195° C.(decomposition), which is sublimed (10⁻² mm Hg/165° C.) to give 338 mg(30%) of N,N'-dicyano-2,5-dichloro-p-benzoquinone bisimine of meltingpoint 225° C. (decomposition). C₈ H₂ Cl₂ N₄ (225.0)

Calculated C 42.70; H 0.90; N 24.90; Cl 31.5; Found C 42.31; H 0.89; N24.93; Cl 31.5.

IR (KBr): 3039 (CH), 2191 (C.tbd.N), 1673 (C═N), 1651 (C═C), 1255, 1050,920, 825, 678 cm⁻¹.-UV (CH₂ -CN): λ_(max) (lgε)=366 sh (4.25), 347(4.40), 254 (3.37) nm.-¹ H-NMR (CDCl₃ /TMS): δ=7.73 ppm (s, 2H).-¹³C-NMR (CDCl₃ /TMS): δ=112.26 (C.tbd.N), 128.18 (C-H), 145.47 (C-Cl),169.27 ppm (C═N).-MS (70 eV): m/e=224 (100%, +).

EXAMPLE 7

Using method GM1, 285 mg (2.00 millimoles) of 2-chloro-p-benzoquinone,379 mg (2.00 millimoles) of TiCl₄ and 820 mg (4.40 millimoles) of (V) in12 ml of CH₂ Cl₂ are reacted, and the mixture is worked up. After areaction time of 3 hours, 136 mg (37%) of crude product are obtained.After sublimation (10⁻² mm Hg/140° C.),N,N'-dicyano-2-chloro-p-benzoquinone bisimine of melting point 158° C.(decomposition) is obtained in 19% yield. IR (KBr): 3041 (CH), 2191(C.tbd.N), 1670 (C═N), 1655 cm⁻¹ (C═C).-¹ H-NMR (CDCl₃ /TMS):δ=7.40-7.83 ppm (m).-MS (70 eV): m/e=190 (100%, M⁺), 155 (10%, M⁺ -Cl),138 (42%, M⁺ -2CN).

EXAMPLE 8

791 mg (5.00 millimoles) of 1,4-naphthoquinone, 2.05 g (11.0 millimoles)of (V) and 947 mg (5.00 millimoles) of TiCl₄ in 30 ml of CH₂ Cl₂ arereacted with one another by general method GM1. After 7 hours, themixture is worked up to give 362 mg (36%) of crude product. Sublimationunder reduced pressure from an oil pump at 160° C. givesN,N'-dicyano-1,4-naphthoquinone bisimine in 29% yield.

C₁₂ H₆ N₄ (206.6) Calculated C 69.75; H 2.93; N 27.12; Found C 70.16; H3.04; N 27.10.

IR (KBr): 3059 (CH), 2180 (C.tbd.N), 1563 (C═C arom.), 1551 (C═N), 1527(C═C), 1355, 1195, 1111, 883, 774 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=399(4.00), 344 sh (4.20), 3.29 (4.30), 278 (4.14), 269 (4.15); 253 nm sh(4.01).-¹ H-NMR (CDCl₃ /TMS): δ=7.65 (s, 2H, olefin. H), 7.88 (m, 2H,H_(A)), 8.44 ppm (m, 2H, H_(B)).-¹³ C-NMR (CDCl₃ /TMS): δ=113.15 (C-1),126.47 (C-2), 130.03 (C-3), 131.29 (C-4), 134.93 (C-5), 175.45 ppm(C-6).-MS (70 eV): m/e=206 (100%, M⁺), 179 (21%, M⁺ HCN), 165 (7% M⁺-HNCN), 154 (34%, M⁺ -2CN), 128 (45%, M⁺ -3CN), 102 (12%, M⁺ -4CN), 101(15%, M⁺ -3CN-HCN), 76 (12%, M⁺ -4CN-C₂ H₄).

EXAMPLE 9

Using method GM1, 554 mg (2.00 millimoles) of 1,5-dichloroanthraquinone,379 mg (2.00 millimoles) of TiCl₄ and 820 mg (4.40 millimoles) of (V)are stirred for 31 hours. Working up gives 511 mg of a mixture, which issubjected to flash chromatography (0.032-0.063 silica gel from Woelm,methylene chloride). Three fractions are obtained:

Fraction 1: 112 mg (20%) of 1,5-dichloroanthraquinone (IR)

Fraction 2: 73 mg (12%) of N-cyano-2,5-dichloro-9,10-anthraquinonemonoimine

Fraction 3: 135 mg (21%) of N,N'-dicyano-1,5-dichloro-9,10-anthraquinonebisimine.

After recrystallization from acetonitrile, 17% ofN,N'-dicyano-1,5-dichloro-9,10-anthraquinone bisimine of melting point313°-315° C. is isolated. IR (KBr): 3070 (CH), 2180 (C.tbd.N), 1599(C═C), 1562 cm⁻¹ (C═N).-UV (CH₃ CN): λ_(max) (lgε)=363 sh (3.35), 306(4.17), 275 nm (4.94).-MS 70 eV): m/e=324 (35%, M⁺), 289 (100%, M⁺ -Cl).

EXAMPLE 10

Reaction of p-benzoquinone with (V) and TiCl₄ (inverse reactionprocedure to method GM1.

216 mg (2.00 millimoles) of p-benzoquinone and 820 mg (4.40 millimoles)of (V) in 6 ml of CH₂ Cl₂ are initially taken, and 379 mg (2.00millimoles) of TiCl₄ in 6 ml of CH₂ Cl₂ are added dropwise in the courseof 10 minutes. The mixture is stirred for 10 minutes, and is worked upas described in Example 4. 81 mg (26%) of N,N'-dicyano-p-benzoquinonebisimine are isolated.

EXAMPLE 11

416 mg (2.00 millimoles) of 9,10-anthraquinone, 820 mg (4.40 millimoles)of (V) and 61 mg (0.40 millimole) of CsF in 20 ml of acetonitrile arestirred for 22 hours, the volatile components are stripped off, thebrown reaction product is extracted with benzene, and the solvent isstripped off to give 341 mg (67%) of yellow crystals. Afterrecrystallization from 8 ml of acetonitrile, 319 mg (62%) ofN,N'-dicyano-9,10-anthraquinone bisimine of melting point 225°-226° C.are isolated. IR (KBr): 3079 (CH), 2171 (C.tbd.N), 1611 (C═C), 1599(C═C), 1564 cm⁻¹ (C═N).-UV (CH₃ CN): λ_(max) (lgε)=332 (4.36), 251 nm(4.54).-¹ H-NMR (60 MHz, CDCl₃ /TMS): δ=7.74-8.04 (m, 4H, H_(A)),8.57-9.07 ppm (m, 4H, H₈).-.sup. 13 C-NMR (CDCl₃ /TMS): δ=113.68 (C-1),127.81 (C-2), 131.68 (C-3), 134.79 (C-4), 171.70 ppm (C-5).-MS (70 eV):m/e=256 (100%, M⁺), 230 (14%, M⁺ -CN), 229 (13%, M⁺ -HCN), 215 (10%, M⁺NHCN), 202 (15%, M⁺ -2HCN).

EXAMPLE 12 N,N'-Dicyano-2,5-dibromo-p-benzoquinone bisimine

3.79 g (20.0 millimoles) of titanium tetrachloride are added to asolution of 2.66 g (10.0 millimoles) of 2,5-dibromo-p-benzoquinone in100 ml of dichloromethane. 4.66 g (25.0 millimoles) ofbistrimethylsilylcarbodiimide in 30 ml of dichloromethane are addeddropwise, during which a dark precipitate separates out from the redsolution. The mixture is stirred for 5.5 hours and then poured onto 250ml of petroleum ether (bp. 39/59° C.), and 6.33 g of dark solid arefiltered off under suction. This is extracted with 50 ml of hot benzene,and 680 mg (22%) of N,N'-dicyano-2,5-dibromo-p-benzoquinone bisimine ofmelting point 239° C. (decomposition) are precipitated with 50 moles ofpetroleum ether (bp. 30/75° C.). Sublimation under reduced pressure froman oil pump at 130° C./4×10⁻⁵ mm Hg gives 228 mg (7%) ofN,N'-dicyano-2,5-dibromo-p-benzoquinone bisimine having the same meltingpoint. IR (KBr): 3043 (C-H), 2179 (C.tbd.N), 1570 (C═N), 1554 (C═C),-1244, 1024, 896, 808, 696 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=264 sh(3.65, 331 sh (4.40), 346 sh (4.56), 348 (4.47), 365 sh nm (4.43).-¹H-NMR (CDCl₃ /TMS): δ=8.07 ppm (s, 2H).-¹³ C-NMR (CDCl₃ /TMS): δ=112.42(C.tbd.N), 132.23 ppm (═C-H).-MS (70 eV): m/e=313 (M⁺, 100%), 233 (M⁺-Br, 37%).

EXAMPLE 13 N,N'-Dicyano-2,5-dimethoxy-p-benzoquinone bisimine

1.90 g (10.0 millimoles) of titanium tetrachloride are added to asolution of 681 mg (5.00 millimoles) of 2,5-dimethoxy-p-benzoquinone in50 ml of dichloromethane, a brown precipitate separating out during thisprocedure. This precipitates redissolves when 4.19 g (22.5 millimoles)of (V) in 20 ml of dichloromethane are added. The solution is stirredfor 3 hours and then poured into 250 ml of petroleum ether (bp. 30/75°C.), the pale brown precipitate is filtered off under suction andsuspended in 70 ml of benzene, and the suspension is heated gently andfiltered. The benzene phase is evaporated down to about 20 ml, and 671mg of an orange solid are precipitated with 50 ml of petroleum ether.600 mg of still moist product are recrystallized from 65 ml of xylene,the solution being filtered while hot. Drying over silica gel gives 143mg (13%) of pure N,N'-dicyano-2,5-dimethoxy-p-benzoquinone bisimine,which sublimes above 190° C. and decomposes above 265° C.

C₁₀ H₈ N₄ O₂ (216.2) Calculated C 55.55; H 3.73; N 25.92; Found C 55.15;H 3.62; N 26.08. IR (KBr): 3036 (C-H), 3007 (C-H), 2954 (C-H), 2179(C.tbd.N), 1589 (C═C), 1569 (C═N), 1312, 1239, 1002, 818 cm⁻¹.-UV (CH₃CN): λ_(max) (lgε)=260 (3.69), 302 sh (3.57), 360 (4.50), 382 sh nm(4.33).-¹ H-NMR (CDCl₃ /TMS) δ=4.03 (s, 6H, OCH₃), 6.54 ppm (s, 2H,═C-H).-¹³ C-NMR (CDCl₃ /TMS) δ=57.76 (C-9.10), 102.03 (C-3.6), 113.38(C-7.8), 162.10 (C-2.5), 170.20 ppm (C-1.4).-MS (70 eV): m/e=216 (M⁺,60%), 161 (M⁺ -CH₃ -NCN, 77%), 93 (100%).-

EXAMPLE 14 N,N'-Dicyano-2,5-di-tert.-butyl-p-benzoquinone bisimine

759 mg (4.00 millimoles) of titanium tetrachloride are added to asolution of 441 mg (2.00 millimoles) of2,5-di-tert.-butyl-p-benzoquinone in 50 ml of dichloromethane, and 1.68g (9.00 millimoles) of (V) in 20 ml of dichloromethane are addeddropwise. After 5 days, the mixture is diluted with 250 ml ofdichloromethane, stirred for 5 minutes with a pinch of powdered activecarbon and then filtered, the filtrate is evaporated down to about 5 ml,and 267 mg of an orange solid of melting point 213°-240° C. areprecipitated with 100 ml of petroleum ether (bp. 30/75° C.). This solidis recrystallized from 10 ml of methylcyclohexane, the solution beingfiltered while hot. 54 mg (10%) of pureN,N'-dicyano-2,5-di-tert.-butyl-p-benzoquinone bisimine, which has amelting point of 241° C. and sublimes above 200° C., are obtained.

C₁₆ H₂₀ N₄ (268.4) Calculated C 71.61; H 7.51; N 20.88; Found C 71.40; H7.60; N 20.99. IR (KBr): 3002 (C-H), 2971 (C-H), 2910 (C-H), 2871 (C-H),2181 (C.tbd.N), 1581 (C═C), 1544 (C═N), 1318, 1228, 1092, 903 cm⁻¹.-UV(CH₃ CN): λ_(max) (lgε)=343 (4.46), 367 sh nm (4.25).-¹ H-NMR (CDCl₃/TMS): δ=1.39 (s, 18H, t-Bu-H), 7.38 pp (s, 2H, ring-H).-¹³ C-NMR (CDCl₃/TMS): δ=29.98 (C-11-16), 36.27 (C-9.10), 112.64 (C-7.8), 128.43(C-3.6), 154.89 (C-2.5), 175.85 ppm (C-1.4).-MS (70 eV): m/e=270 (M⁺+2H, 16%), 268 (M⁺, 71%), 253 (M⁺ -CH₃), 100%), 238 (M⁺ -2CH₃, 18%), 228(M⁺ -NCN, 40%), 226 (M⁺ -2CN, 28%), 212 (M⁺ -2CH₃ -CN, 50%), 211 (M⁺-2CH₃ -HCN, 34%), 201 (M⁺ -NCN-HCN, 25%), 200 (M⁺ -HNCN-HCN, 30%), 199(M⁺ -H₂ NCN-HCN, 25 %), 185 (M⁺ -t-Bu-Cn, 41%), 172 (M⁺ -2CH₃ -NCH-CN,44%).

EXAMPLE 15 N,N'-Dicyano-2,5-diphenyl-p-benzoquinone bisimine

759 mg (4.00 millimoles) of titanium tetrachloride and, thereafter, asolution of 1.49 g (8.00 millimoles) of (V) in 10 ml of dichloromethaneare added to a solution of 520 mg (2.00 millimoles) of2,5-diphenyl-p-benzoquinone in 50 ml of dichloromethane. The mixture isstirred for 8 hours, filtered over 0.062-0.200 silica gel from Woelm andthen evaporated down in a rotary evaporator to give 440 mg (71%) of ared solid of melting point 305° C. (decomposition). 424 mg of productare recrystallized from 10 ml of toluene, and 332 mg (54%) of pureN,N'-dicyano-2,5-diphenyl-p-benzoquinone bisimine are obtained in theform of orange crystals of melting point 311° C. (decomposition).

IR (KBr): 2173 (C.tbd.N), 1581 (C-C), 1561 (C═C), 1540 (C═N), 1444,1223, 894, 720, 705 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=237 (4.31), 340(4.30), 387 sh nm (3.95).-¹ H-NMR (CDCl₃ /TMS): δ=7.47 (s, 10H,aromatic-H), 7.52 ppm (s, 2H, quinone-H).-¹³ C-NMR (CDCl₃ /TMS):δ=113.32 (C-7.8), 127.90 (C-3.6), 128.76 (C-4'), 130.07 (C-3'), 131.00(C-2'), 132.24 (C-1'), 147.66 (C-2.5), 175.25 (C-1.4).-MS (70 eV):m/e=308 (M⁺, 100%), 282 (M⁺ -CN, 10%), 281 (M⁺ -HCN, 25%), 280 (M⁺ -H₂CN, 57 %), 268 (M⁺ -NCN, 13%), 266 (M⁺ -H₂ NCN, 10%).

EXAMPLE 16 N,N'-Dicyano-2,6-dimethyl-p-benzoquinone bisimine

759 mg (4.00 millimoles) of titanium tetrachloride are added to 272 mg(2.00 millimoles) of 2,6-dimethyl-p-benzoquinone in 40 ml ofdichloromethane. 1.68 g (9.00 millimoles) of (V) in 20 ml ofdichloromethane are added dropwise, a precipitate separating out fromthe red solution during this procedure. The mixture is stirred for 9hours, after which it is filtered over 0.062-2.00 silica gel from Woelm,and the filtrate is evaporated down in a rotary evaporator to give 269mg of a product of melting point 70°-110° C. This product isrecrystallized from 16 ml of cyclohexane, the solution being filteredwhile hot, and 57 mg (15%) of N,N'-dicyano-2,5-dimethyl-p-benzoquinonebisimine are obtained in the form of yellow crystals of melting point116°-119° C.

C₁₀ H₈ N₄ (184.2) Calculated C 65.20; H 4.38; N 30.42; Found C 64.84; H4.43; N 30.40. IR (KBr): 3040 (C-H), 2962 (C-H), 2168 (C.tbd.N), 1587(C═C), 1563 (C═N).-UV (CH₃ CN): λ_(max) (lgε)=332 sh (4.40), 338 (4.51),351 (4.47), 380 sh nm (3.45).-¹ H-NMR (CDCl₃ /TMS): δ=2.43 (broad s, 6H,CH₃), 6.96 (broad s, 1H, anti-H), 724 (broad s, 1H, syn-H).-¹³ C-NMR(CDCl₃ /TMS): δ=19.38 (C-9), 19.53 (C-10), 112.86 (C-8), 113.59 (C-7),126.98 (C-3), 135.44 (C-5), 173.19 (C-4), 174.52 (C-1); C-2 and C-6cannot be detected because of excessive broadening of the signal.

EXAMPLE 17

1.90 g (10.0 millimoles) of titanium tetrachloride are added to asolution of 596 mg (4.00 millimoles) of trimethyl-p-benzoquinone in 50ml of dichloromethane. 4.20 g (32.5 millimoles) of (V) in 20 ml ofdichloromethane are added dropwise to the resulting red solution, themixture is stirred for 7 hours and then run into 400 ml of petroleumether (30/75° C.), the resulting mixture is filtered under suction, andthe mother liquor is evaporated down in a rotary evaporator to give 2.15g of an oily orange solid. This is recrystallized from 14 ml ofmethylcyclohexane to give 151 mg (19%) ofN,N'-dicyano-2,3,5-trimethyl-p-benzoquinone bisimine in the form ofyellow crystals of melting point 120° C. (decomposition). This productis stirred in 30 ml of carbon tetrachloride, the solution is filteredand the filtrate is evaporated down in a rotary evaporator. 118 mg (15%)of N,N'-dicyano-2,3,5-trimethyl-p-benzoquinone bisimine of melting point122° C. are isolated. IR (KBr): 2178 (CN), 2158 (C.tbd.N), 1633 (C═C),1556 (C═N), 1382 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=324 sh (4.36), 341(4.46), 355 sh nm (4.40).-¹ H-NMR (CDCl₃ /TMS): δ=2.28 (s, 3H, H_(A)),2.40 (s, 3H, H_(B)), 2.48 (s, 3H, H_(C)), 7.32 ppm (s, 1H, H_(D)).-¹³C-NMR (CDCl₃ /TMS): δ=15.59 (C-10), 16.00 (C-9), 19.41 (C-11), 113.01(C-7), 113.65 (C-8), 127.06 (C-6), 142.12 (broad, weak, C₃.5), 173.32(C-4), 175.05 (C-1).-MS (70 eV): m/e=200 (M⁺ +2H, 13%), 198 (M⁺, 39%),174 (M⁺ +2H-CN, 100%), 170 (M⁺ +2H-2CH₃, 17%), 146 (M⁺ -2CH, 81%), 145(M⁺ -CN-HCN, 87%), 132 (M⁺ -2CN-CH₃).

EXAMPLE 18

759 mg (4.00 millimoles) of titanium tetrachloride are added to asolution of 328 mg (2.00 millimoles) of tetramethyl-p-benzoquinone in 50ml of dichloromethane, and the mixture is stirred until a yellowprecipitate appears, which takes 5 minutes. 1.68 g (9.00 millimoles) of(V) in 20 ml of dichloromethane are then slowly added dropwise, andstirring is continued for 19 hours. Thereafter, the reaction mixture isfiltered through 0.062-0.200 silica gel from Woelm, the solvent isevaporated off in a rotary evaporator, and 223 mg (53%) of crude productof melting point 110°-123° C. (decomposition) are obtained. 84 mg ofproduct are recrystallized from 5 ml of cyclohexane, and 78 mg (49%) ofN,N'-dicyanotetramethyl-p-benzoquinone-bisimide of melting point125°-127° C. (decomposition) are isolated as long orange needles.

C₁₂ H₁₂ N₄ (212.2) Calculated C 67.95; H 5.70; N 26.40; Found C 67.65; H5.67; N 26.18.

IR (KBr): 2149 (C.tbd.N), 1576 (C═C), 1560 (C═N), 1381, 678 cm⁻¹.-UV(CH₃ CN): λ_(max) (lgε)=331 sh (3.87), 346 (4.37), 368 sh nm (4.15).-¹H-NMR (CDCl₃ /TMS): δ=2.37 ppm (s, 12H, CH₃).-¹³ C-NMR (CDCl₃ /TMS):δ=15.50 (CH₃), 113.25 (C.tbd.N), 138.98 (C-CH₃), 173.99 ppm (C═N).-MS(70 ^(e) V): m/e=212 (M⁺, 100%), 185 (M⁺ -HCN, 28%), 170 (M⁺ -HCN-CH₃,30%), 160 (M⁺ -2CN, 92%), 159 (M⁺ -HCN-CN, 35%), 158 (M⁺ -3HCN, 26%),145 (M⁺ -2CN-2CH₃, 65%).

EXAMPLE 19

759 mg (4.00 millimoles) of titanium tetrachloride are added to 456 mg(2.00 millimoles) of tetramethoxy-p-benzoquinone in 50 ml ofdichloromethane, and 168 g (9.00 millimoles) ofbistrimethylsilylcarbodiimide in 10 ml of dichloromethane are addeddropwise to the resulting black solution. The mixture is stirred for 8hours, after which it is diluted with 250 ml of dichloromethane, stirredfor 5 minutes with a large pinch of powdered active carbon, filtered andthen evaporated down to about 20 ml, and 516 mg (93%) of a solid ofmelting point 153°-175° C. are precipitated with 200 ml of petroleumether (30/75° C.). This solid is recrystallized from 20 ml of benzene,the solution being filtered while hot, and 256 mg of needles of meltingpoint 172°-173° C. are obtained. A further 75 mg of product of the samemelting point are precipitated from the mother liquor with 50 ml ofpetroleum ether (30/75° C.). The total yield is 59% ofN,N'-dicyanotetramethoxy-p-benzoquinone bisimine.

C₁₂ H₁₂ N₄ O₄ (276.2) Calculated C 52.17; H 4.38; N 20.29; Found C51.92; H 4.09; N 20.04. IR (KBr): 2951 (C-H), 2948 (C-H), 2160(C.tbd.N), 1592 (C═C), 1554 (C═N), 1458, 1442, 1198, 1083, 998, 910,854, 727, 697, 653 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=356 sh (4.48), 368nm (4.54).-¹ HNMR (CDCl₃ /TMS): δ=4.03 ppm (broad s, 12H, OCH₃).-¹³C-NMR (CDCl₃ /TMS): δ=62.02 (OCH₃), 62.08 (OCH₃), 112.89 (C═N), 144.26(C-OCH₃), 166.52 ppm (C═N).-MS (70 eV): m/e=292, 276 (M⁺, 100%), 261 (M⁺-CH₃, 60%).

EXAMPLE 20

12.1 g (64.8 millimoles) of titanium tetrachloride are added to 492 mg(2.00 millimoles) of chloranil in 50 ml of dichloromethane, and 9.32 g(50.0 millimoles) of (V) in 20 ml of dichloromethane are added dropwiseto the resulting dark yellow suspension. The precipitate disappears, thesolution becomes red and then changes to black, and orange-red crystalsare precipitated from the black solution after some time. The mixture isstirred for 30 hours, after which the precipitate is filtered off undersuction and extracted with hot benzene. The solvent is evaporated downto 10 ml, and 359 mg (61%) of orange-red crystals of melting point252°-255° C. (decomposition) are precipitated with 50 ml of petroleumether (30/75° C.).

324 mg of product are recrystallized from 20 ml of acetonitrile, and 140mg (26%) of N,N'-dicyanotetrachloro-p-benzoquinone bisimine are isolatedas orange crystals of melting point 258° C. (decomposition).

C₈ Cl₄ N₄ (293.9) Calculated C 32.69; N 19.07; Found C 32.33; N 19.04.

IR (KBr): 2178 (C.tbd.N), 2155 (C.tbd.N), 1576 (C═C), 1516 (C═N), 1160,1146, 1133, 1090, 842, 738 (C-Cl), 680 cm⁻¹.-UV (CH₃ CN): λ_(max)(lgε)=309 sh (3.75), 327 sh (4.20), 344 sh (4.47), 353 (4.48), 361 sh(4.51), 366 (4.52), 372 sh nm (4.45).-MS (70 eV): m/e=292 (M⁺, 45%), 257(M⁺ -Cl, 20%), 240 (M⁺ -2CN, 58%), 205 (M⁺ -Cl-2CN, 23%), 111 (M⁺--Cl--C₂ Cl₂ --2CN, 100%).

N,N'-Dicyanoquinone bisimines of the formula (I) are prepared by thegeneral method (GM2) below.

Titanium tetrachloride is added to a solution of the quinone (IV) indichloromethane in the absence of moisture, and, as a rule, a yellow ororange precipitate separates out. Bistrimethylsilylcarbodiimide (V) in alittle dichloromethane is rapidly added dropwise, the dark reactionmixture is stirred at room temperature and the poured onto ice water,the organic phase is separated off and dried over anhydrous magnesiumsulfate, and the organic solution is evaporated down in a rotaryevaporator until the first crystals are precipitated. Precipitation iscompleted by adding petroleum ether (30/75° C.). The crystals are thenrecrystallized from the solvent stated in the table below. Thebiscyanoquinone imines stated in Examples 21 to 34 are prepared by thismethod. The amounts of (IV), (V), titanium tetrachloride and methylenechloride, the reaction time and the yield of biscyanoquinone bisimineare summarized in the table below. The biscyanoquinone bisimines arecharacterized by their melting points.

Method GM2 aboves gives the dicyanoquinone bisimines in higher yield andbetter purity than method GM1.

EXAMPLES 21 TO 34 ##STR16##

    __________________________________________________________________________                                              Reac-                               Ex-                      IV  V   TiCl.sub.4                                                                             tion                                am-                      milli-                                                                            milli-                                                                            milli-                                                                            CH.sub.2 Cl.sub.2                                                                  time                                                                              Yield                                                                             Recrystallized                                                                        Mp.                 ple                                                                              R.sup.1                                                                              R.sup.2                                                                           R.sup.3                                                                             R.sup.4                                                                            moles                                                                             moles                                                                             moles                                                                             [ml] [hours]                                                                           [%] from    [°C.]        __________________________________________________________________________    21 CH.sub.3                                                                             H   CH.sub.3                                                                            H    2   12  10  30   1   42  cyclohexane                                                                           125-126             22 CH.sub.3                                                                             CH.sub.3                                                                          H     H    10  60  50  40   3   43  methylcyclo-                                                                          173-175                                                               hexane/toluene              23 CH.sub.3                                                                             CH.sub.3                                                                          H     CH.sub.3                                                                           4   20  15  50   3   35  methylcyclo-                                                                          125-126                                                               hexane                      24 C.sub.2 H.sub.5                                                                      H   C.sub.2 H.sub.5                                                                     H    2   12  10  30   1   39  cyclohexane                                                                             64-64.5           25 C(CH.sub.3).sub.3                                                                    H   C(CH.sub.3).sub.3                                                                   H    2   25  10  60   26  58  methylcyclo-                                                                          241                                                                   hexane                      26 OCH.sub.3                                                                            H   H     OCH.sub.3                                                                          2   12  10  30   1   84  o-dichloro-                                                                           265                                                                   benzene                     27 Cl     H   H     CH.sub.3                                                                           4    9   8  40   8   .sup. 42.sup.a                                                                    benzene 179-182             28 Cl     H   Cl    H    2   12  10  30   1   25  methylcyclo-                                                                          128-130                                                               hexane                      29 Cl     CH.sub.3                                                                          CH.sub.3                                                                            Cl   2   25  20  50   2.5 52  acetic                                                                                >350                30 CH.sub.3                                                                             H                                                                                            2   12  10  40   2.5 63  toluene/methyl-                                                               cyclohexane                                                                           >35                 31 Cl     H                                                                                  ##STR17## 2   12  10  40   2   63  acetonitrile                                                                          192                 32                                                                                ##STR18##                                                                                ##STR19## 2   25  10  70   21  .sup. 28.sup.a                                                                    toluene/methyl-                                                               cyclohexane                                                                           166                 33                                                                                ##STR20##                                                                                ##STR21## 2   25  10  70   23  77  acetonitrile                                                                          222-223             34                                                                                ##STR22##                                                                                ##STR23## 5   30  20  180  3   .sup. 34.sup.a                                                                    DMSO    329-330             __________________________________________________________________________     .sup.a The reaction mixture is poured into petroleum ether, the               precipitate is filtered off under suction and extracted with hot benzene,     the benzene extract is evaporated down, and the dicyanoquinone bisimine i     precipitated with petroleum ether.                                            DMSO = dimethyl sulfoxide.                                               

EXAMPLE 35

A hot solution of 51 mg (0.250 millimole) of tetrathiafulvalene in 5 mlof acetonitrile is poured into a hot solution of 56 mg (0.249 millimole)of N,N'-dicyano-2,5-dichloro-p-benzoquinone bisimine in 5 ml ofacetonitrile. The product is filtered off under suction, washed with alittle ether and dried to give 105 mg (98%) of a black charge transfercomplex having a donor/acceptor ratio of 1:1 and a melting point of 350°C.

C₁₄ H₆ Cl₂ N₄ S₄ (429.4) Calculated C 39.16; H 1.41; N, 13.05%; Found C38.88; H 1.13; N 13.05. (KBr): 2122 cm⁻¹ (C.tbd.N).

EXAMPLE 36

190 mg (605 μmoles) of N,N'-dicyano-2,5-dibromo-p-benzoquinone bisimineare dissolved in 45 ml of dichloromethane, this solution is filteredinto a flask, and a solution of 124 mg (605 μmoles) oftetrathiafulvalene in 10 ml of dichloromethane is added. The darkprecipitate which immediately separates out is stirred for 0.5 hour,after which the mixture is filtered under suction and the residue iswashed with a little dichloromethane and dried over silica gel to give283 mg (90%) of the 1:1 charge transfer complex of tetrathiafulvaleneand N,N'-dicyano-2,5-dibromo-p-benzoquinone bisimine in the form of aviolet solid of melting point 350° C.

C₁₄ H₆ Br₂ N₄ S₄ (518.3) Calculated C 32.44; H 1.17; N 10.81; Found C32.60. H 0.96; N 10.89.

IR (KBr): 3088 (C-H), 2122 (C.tbd.N), 1557 (C═C), 1502 (C═N), 1352, 1037cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=256 (3.64), 290 sh (3.88), 297 (3.92),349 sh (4.29), 361 sh (4.39), 363 (4.40), 364 sh (3.39), 425 sh (4.17),430 (4.19), 459 sh (3.87), 464 sh (3.84), 475 sh (3.67), 484 (3.68), 574(3.97), 605 sh (4.06), 620 sh (4.16), 622 (4.17), 632 sh (4.09), 666 sh(4.00), 686 sh (4.24), 688 nm (4.25).

EXAMPLE 37

(a) A solution of 102 mg (500 μmoles) of tetrathiafulvalene in 10 ml ofacetonitrile is added to a hot solution of 103 mg (500 μmoles) ofN,N'-dicyano-1,4-naphthoquinone bisimine in 20 ml of acetonitrile. Thegreen solution is refluxed for 2 hours, after which a further 102 mg(500 μmoles) of tetrathiafulvalene are added and half the solvent isstripped off, a black solid crystalling out. The mixture is heated onceagain until all solid material has dissolved, after which the solutionis allowed to cool. The charge transfer complex crystallizes outtogether with the sparingly soluble bisimine. After 6 days, thin blackglossy needles as long as one cm have grown in the solution. Theseneedles are the charge transfer complex of tetrathiafulvalene andN,N'-dicyano-1,4-naphthoquinone bisimine, and are separated off andwashed with a little acetonitrile.

(b) A solution of 306 mg (1.50 millimoles) of tetrathiafulvalene in 5 mlof acetonitrile is poured over 103 mg (500 μmoles) ofN,N'-dicyano-4,4-naphthoquinone bisimine in a conical flask, and themixture is left to stand for 30 days in the closed flask. The product isfiltered off under suction and dried, and 204 mg (100%) of themicrocrystalline 1:1 charge transfer complex of tetrathiafulvalene andN,N'-dicyano-1,4-naphthoquinone bisimine are obtained. This complexdecomposes above 163° C.

C₁₈ H₁₀ N₄ S₄ (411.0) Calculated C 52.60; H 2.45; N 13.64; S 31.20;Found C 52.55; H 2.32; N 13.47; S 31.02.

UV (CH₃ CN): λ_(max) (lgε)=268 sh (5.00), 271 (5.01), 277 (5.03), 317 sh(5.22), 320 (5.23), 349 sh (4.95), 379 sh (4.80), 460 sh (3.79), 480(3.25), 486 sh (3.24), 354 sh (2.80), 572 (2.72), 590 (2.78), 598 sh(2.72), 645 nm (2.85).

The conductivity measured on isolated crystals was 25 Ω⁻¹. cm⁻¹.

EXAMPLE 38

A solution of 204 mg (2.00 millimoles) of tetrathiafulvalene in 5 ml ofacetonitrile is added to a suspension of 184 mg (1.00 millimole) ofN,N'-dicyano-2,5-dimethyl-p-benzoquinone bisimine in 10 ml ofacetonitrile at 50° C. The mixture is stirred for 1 hour at thistemperature and the warm green solution is filtered and left to standfor 6 hours. During this time, black rods as long as about 2 mmcrystallize out. 99 mg (26%) of the charge transfer complex oftetrathiafulvalene and N,N'-dicyano-2,5-dimethyl-p-benzoquinone bisimineof melting point 147° C. (decomposition) are isolated.

C₁₆ H₁₂ N₄ S₄ (388.5) Calculated C 49.49; H 3.11; N 14.47; Found C49.74; H 3.15; N 14.03.

IR (KBr): 2157 (C.tbd.N), 1582 (C═C), 1535 (C═N), 1320, 1278, 1246, 882,797, 731, 683, 665 cm⁻¹.-UV (CH₃ CN): λ_(max) (lgε)=300 sh (4.30), 325(4.50), 342 (4.48), 349 sh (4.44), 362 sh nm (4.24).

EXAMPLE 39

A solution of 55 mg (352 μmoles) of N,N'-dicyano-p-benzoquinone bisiminein 25 ml of absolute acetonitrile is added to a solution of 72 mg (352μmoles) of tetrathiofulvalene in 25 ml of absolute acetonitrile underN₂. Black needles are precipitated immediately. These are filtered offunder suction, washed with absolute acetonitrile and absolute ether anddried over silica gel under 20 mm Hg and at 50° C. 114 mg (90%) of the1:1 charge transfer complex of N,N'-dicyano-p-benzoquinone bisimine andtetrathiofulvalene are obtained, the complex having a melting point of350° C.

C₁₄ H₈ N₄ S₄ (360.5) Calculated C 46.64; H 2.24; N 15.54; Found C 46.00;H 2.24; N 15.91.

IR (KBr): 2120 cm⁻¹ (C.tbd.N).-UV (acetonitrile): λ_(max) (lgε)=316(4.19), 359 (4.29), 509 sh (3.34), 522 sh (3.45), 547 sh (3.67), 559 sh(3.79), 569 (3.84), 584 sh (3.84), 613 (4.07), 678 (4.12), 1903 (3.68),1940 nm sh (3.02).

Conductivity (crystal powder): δ=6.1 Ω⁻¹. cm⁻¹.

EXAMPLES 40 TO 43

A warm solution of tetrathiafulvalene (IIa) in anhydrous acetonitrile isadded to a solution or suspension of the dicyanoquinone bisimine (Ia) inanhydrous acetonitrile. The molar ratio of (Ia) to (IIa) is 1:1 or 1:2.The crystals formed are filtered off under suction and washed with alittle dichloromethane or acetonitrile, and the complex is dried oversilica gel at room temperature.

    __________________________________________________________________________     ##STR24##                                                                                   (VI)                                                           (Va)           Yield  Mp.      Analysis                                       Example                                                                            R.sup.1                                                                            R.sup.4                                                                            (% of theory)                                                                        [°C.]                                                                           C  H  N                                        __________________________________________________________________________    40   CH.sub.3                                                                           H    75     140                                                                              calculated                                                                          48.11                                                                            2.69                                                                             14.96                                                             found 48.45                                                                            2.47                                                                             15.32                                    41   CH.sub.3                                                                           Cl   94     144                                                                              calculated                                                                          44.05                                                                            2.22                                                                             13.70                                                             found 43.80                                                                            2.21                                                                             13.71                                    42   Cl   H    87     220                                                                              calculated                                                                          42.58                                                                            1.79                                                                             14.19                                                             found 42.52                                                                            1.36                                                                             13.98                                    43   OCH.sub.3                                                                          OCH.sub. 3                                                                         56     199                                                                              calculated                                                                          45.69                                                                            2.88                                                                             13.33                                                             found 46.04                                                                            2.75                                                                             13.12                                    __________________________________________________________________________

EXAMPLES 44 TO 46

The procedure described in Examples 40 to 43 is followed, except thattetrathiafulvalene is replaced by the equivalent amount ofdibenzotetrathiafulvalene (IIa).

    ______________________________________                                         ##STR25##                                                                     ##STR26##                                                                             (VII)                                                                Ex-            Yield              Analysis                                    am-  (Va)      (% of   Mp.          C    H    N                               ple  R.sup.1                                                                              R.sup.4                                                                              theory)                                                                             [°C.] [%]  [%]  [%]                           ______________________________________                                        44   H      H      37.sup.1                                                                            140  calculated                                                                            57.37                                                                              2.63 12.17                                                       found   57.39                                                                              2.45 12.19                         45   Cl     Cl     41.sup.2                                                                            227  calculated                                                                            51.85                                                                              2.18 6.72                                                        found   51.52                                                                              2.12 6.69                          46   Br     Br     57.sup.2                                                                            229  calculated                                                                            46.85                                                                              1.97 6.07                                                        found   46.87                                                                              1.66 6.22                          ______________________________________                                         .sup.1 1:1 complex                                                            .sup.2 The ratio of acceptor to donor in the complex is 1:2              

We claim:
 1. A charge transfer complex of a biscyanimine of the formula##STR27## and a compound of the formula ##STR28## where R¹, R², R³ andR⁴ independently of one another are each hydrogen, methyl, ethyl,methoxy, ethoxy, chlorine or bromine, or one of the radicals R¹ and R²or one of the radicals R³ and R⁴ is phenyl or tert.-butyl, or one of theradicals R¹ and R² and one of the radicals R³ and R⁴ are each phenyl ortert.-butyl, or R₁ and R₂ taken together, or R₃ and R₄ taken togetherindependently form a ##STR29## and the fused-on aromatic rings areunsubstituted or monosubstituted or disubstituted by chlorine, bromineor methyl, and R⁵, R⁶, R⁷ and R⁸ independently of one another are eachhydrogen, methyl, ethyl, phenyl, methylphenyl or methoxyphenyl, or R₅and R₆ taken together, or R₇ and R₈ taken together, independently form a##STR30## and X and Y independently of one another are each S or Se. 2.A charge transfer complex as claimed in claim 1, wherein the molar ratioof the biscyanodiimine (I) to the tetrathiafulvalene (II) is 1:1 or 1:2.3. A charge transfer complex as claimed in claim 1, wherein R¹ and R⁴independently of one another are each chlorine, bromine, methyl, ethyl,tert.-butyl, methoxy or phenyl, R² and R³ are each hydrogen, methyl orchlorine, R⁵, R⁶, R⁷ and R⁸ are each hydrogen, or R⁵ and R⁸ are eachmethyl or phenyl and R⁶ and R⁷ are each hydrogen, X and Y are each S,and the molar ratio of (I) to (II) is 1:1.
 4. A charge transfer complexas claimed in claim 1, wherein R¹ and R⁴ are each hydrogen, chlorine,bromine, methoxy, methyl, tert.-butyl or phenyl, R² and R³ are eachhydrogen, R₅ and R₆ taken together and R₇ and R₈ taken together are each##STR31## X and Y are each S, and the ratio of (I) to (II) is 1:1 or1:2.
 5. A biscyanimine of the formula ##STR32## where R¹, R², R³ and R⁴independently of one another are each hydrogen, methyl, ethyl, methoxy,ethoxy, chlorine or bromine, or one of the radicals R¹ and R² or one ofthe radicals R³ and R⁴ is phenyl or tert.-butyl, or one of the radicalsR¹ and R² and one of the radicals R³ and R⁴ are each phenyl ortert.-butyl, or R₁ and R₂ taken together, or R₃ and R₄ taken together,independently form a ##STR33## wherein the fused-on aromatic rings areunsubstituted or monosubstituted or disubstituted by chlorine, bromineor methyl.
 6. A biscyanimine as claimed in claim 5, wherein R¹ and R⁴are each hydrogen, methyl, tert.-butyl, phenyl, methoxy, chlorine orbromine and R² and R³ are each hydrogen, methyl, methoxy or chlorine, orR¹ and R² form ##STR34## and R³ and R⁴ are each hydrogen or togetherform ##STR35##
 7. A biscyanimine as claimed in claim 5, wherein R¹ andR⁴ are each hydrogen, methyl, tert.-butyl, phenyl, chlorine or bromine,and R² and R³ are each hydrogen, or R¹ and R² together form ##STR36##and R³ and R⁴ are each hydrogen.
 8. A process for the preparation of abiscyanimine of the formula ##STR37## where R¹, R², R³ and R⁴independently of one another are each hydrogen, methyl, ethyl, methoxy,ethoxy, chlorine or bromine, or one of the radicals R¹ and R² or one ofthe radicals R³ and R⁴ is phenyl or tert.-butyl, or one of the radicalsR¹ and R² and one of the radicals R³ and R⁴ are each phenyl ortert.-butyl, or R₁ and R₂ taken together, or R₃ and R₄ taken together,independently form a ##STR38## and the fused-on aromatic rings areunsubstituted or monosubstituted or disubstituted by chlorine, bromineor methyl, wherein a quinone of the formula ##STR39## where R¹, R², R³and R⁴ have the above meanings, is reacted withbistrimethylsilylcarbodiimide in a molar ratio of 1:2, in the presenceof a catalyst and in an inert organic liquid.
 9. A process as claimed inclaim 8, wherein the catalyst used is cesium fluoride, a crownether/potassium cyanide or titanium tetrachloride.
 10. A process asclaimed in claim 9, wherein the catalyst used is titanium tetrachloride.11. A process as claimed in claim 8, wherein from 2.2 to 3 moles ofbistrimethylsilylcarbodiimide are employed per mole of quinone.
 12. Aprocess as claimed in claim 9, wherein from 2.2 to 3 moles ofbistrimethylsilylcarbodiimide are employed per mole of quinone.
 13. Aprocess as claimed in claim 10, wherein from 2.2 to 3 moles ofbistrimethylsilylcarbodiimide are employed per mole of quinone.